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Differentiation fate of a stem-like CD4 T cell controls immunity to cancer
Maria A. Cardenas. et al.
Nature. 2024
In tumor immunity, the role of CD8+ T cells is relatively mature, but the mechanism affecting the anti-tumor effect of CD4+ T cells is still unclear.They performed single-cell RNA sequencing (scRNA-seq) on PD1+ CD45RA− CD4 T cells infiltrating human kidney tumours. They identified three clusters that expressed genes related to antigenic stimulation and tissue migration. Cluster 3 cells did not express any of the major lineage-defining transcription factors (BCL6, TBX21, GATA3 or RORC). These CD4 T cells instead expressed high levels of TCF7. Furthermore, TCF7-expressing CD4 T cells were significantly enriched for a human stem-like CD8 T cell gene signature. TCF1+ lin− CD4 T cells underwent extensive proliferation and retained their activated but uncommitted phenotype, whereas CD39+ cells remained undivided. PD1+ TCF1+ lin− or CD39+ CD4 T cells were sorted from human tumours as described above and cultured in cytokine polarization conditions towards TH1, Treg, TFH or EOMES lineages. TCF1+ lin− CD4 T cells downregulated TCF1 and upregulated TBET and GZMB in response to TH1 cell polarization, whereas they upregulated FOXP3 and CD25 in response to Treg cell polarization.PD1+ TCF1+ lin− CD4 T cells underwent extensive proliferation, maintained CD26 expression, and downregulated markers inversely associated with T cell receptor (TCR) stimulation. Following inoculation with TRAMPC1-GP, GP66+ CD4 T cells underwent expansion in TDLNs and persisted throughout the five-week response. Five weeks after tumour inoculation, GP66+ CD4 T cells in TDLNs all expressed activation markers and primarily exhibited a TCF1+ lin−, FOXP3+ or BCL6+ phenotype, with very few cells expressing TBET, RORγt or EOMES.In contrast to TDLNs, GP66+ CD4 T cells in tumours were primarily Treg cells, with a smaller proportion of cells retaining a TCF1+ lin− phenotype.Over the four- to five-week tumour response, 20% and 85% of transferred SMARTA CD4 T cells expressed FOXP3 within TDLNs and tumours, respectively, with minimal expression of TBET, RORγt or BCL6.FOXP3+ Treg cell depletion three to four weeks after TRAMPC1-GP tumour inoculation in DEREG mice12 (denoted as FOXP3-DTR) resulted in significant tumour-specific GP66+ CD4 T cell expansion and TH1 differentiation in TDLNs and tumours.Differentiated GP66+ TH1 CD4 T cells exhibited downregulation of TCF1 and increased expression of TBET and other known TH1 markers, along with increased production of IFNγ and IL-2. Notably, TCRβ sequencing showed that whereas in untreated conditions, stem-like CD4 T cells shared clonality with Treg and TFH populations in TDLNs, stem-like CD4 T cells from Treg-depleted mice shared more than 90% of clonotypes with the clonally expanded TH1 cluster. Given the notable effect of inducing stem-like CD4 to TH1 differentiation on restoring effector CD8 T cell generation in TDLNs, we next investigated potential mechanisms. NicheNet sender-receiver analysis predicted IFNγ from TH1 CD4 T cells as a top candidate ligand for induction of transcriptional changes related to effector differentiation on LN-stem CD8 T cells. They generated Ifng knockout (KO) TetON TBET SMARTAs using a CAS9 electroporation system followed by transfer into mice with established TRAMPC1-GP tumours. Compared to TetON SMARTAs, Ifng-KO TetON SMARTAs were unable to control TRAMPC1-GP tumours despite the addition of anti-PDL1 therapy.Ifng-KO TetON SMARTAs did not induce endogenous GP66+or bulk PD1+CD4 T cell differentiation to TH1 cells in TDLNs and tumours, suggesting that IFNγ also has a role in altering the fate of stem-like CD4 T cells.
DOI: 10.1038/s41586-024-08076-7
02
Carlos G Ardanaz et al.
Sci Adv. 2024
Astrocytes play a key role in maintaining brain function and metabolism. They found that knockdown of astrocyte GLUT1 expression significantly reduces glucose uptake, decreases the rate of glycolysis, and decreases the concentration of extracellular lactate. Further experiments showed that the dependence of astrocytes on glutamine increased after knockdown of GLUT1, indicating that astrocytes could use other energy substances instead of glucose to meet energy requirements. They found that astrocytes GLUT1 knockout mice (GLUT1-∆ GFAP mice for short) did not disrupt the integrity of the blood-brain barrier, and astrocytes branched more, the total length increased, and there were morphological structural changes. Astrocytes in the brains of GLUT1-∆ GFAP mice have reduced uptake of carbon-13-labeled glucose and decreased lactate concentrations in the hypothalamus and hippocampal brain regions compared to normal mice. There was no difference in body weight between GLUT1-∆ GFAP mice after ingestion of conventional or high-fat food. GLUT1 knockout of astrocytes under conventional diet did not affect the appetite increase caused by fasting and did not affect glucose tolerance, but GLUT1-∆GFAP mice inhibited the appetite increase caused by fasting or intraperitoneal glucose injection after a high-fat diet, and this inhibition enhancement was accompanied by increased insulin secretion. White fat (BAT) in mammals, the former is mainly used to store calories, and brown fat (BAT), which is responsible for consuming energy. Wild-type mice gained weight and formed excessive brown fat after a high-fat diet, but GLUT1-∆ GFAP mice did not form excessive brown fat after ingesting high-fat food. The hypothalamus is a key brain region that regulates feeding behavior, and POMC neurons in the arcuate nucleus (ARC) brain region have the effect of appetite suppression. Both conventional and high-fat foods can activate POMC neurons in the ARC brain region of GLUT1-∆GFAP mice. Knockdown of astrocyte GLUT1 in the ARC brain region also improves glucose tolerance. Astrocytes secrete glutamate, D-serine, and ATP, which regulate the activity of neighboring neurons. In vitro cell experiments showed that the levels of glutamate and D-serine in the medium did not change after knocking down the expression of GLUT1 in astrocytes, but the levels of ATP increased. ATP levels in GLUT1-∆GFAP mice increased after intraperitoneal glucose injection. Non-selective P2 purine receptor antagonists can significantly block the improvement of peripheral glucose metabolism in GLUT1-∆GFAP mice. The release of ATP by astrocytes is dependent on insulin signaling. Increased expression of insulin receptor IR in astrocytes of GLUT1-∆GFAP mice. ATP levels did not increase after intraperitoneal glucose injection, with specific knockout astrocyte insulin receptor IR mice (IR-∆ GFAP mice). The decrease in cerebrospinal fluid glucose concentration and glucose utilization capacity in IR-∆GFAP mice also inhibited the appetite increase caused by intraperitoneal injection of glucose, which improved glucose tolerance and restored the appetite increase caused by glucose injection after injection of non-selective P2 purine receptor agonists. In addition, specific knockout of insulin receptor IR in astrocytes of GLUT1-∆GFAP mice (knockout of both GLUT1 and IR) decreased glucose utilization and could not enhance peripheral glucose metabolism.
DOI: 10.1126/sciadv.adp1115
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